Like it says what is the easiest way to check it. Just pull the plugs and look down the hole? I can't see much. I have been playing with the jetting and I want to keep an eye on it.

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Pull exhaust off, shine a light into the exhaust port with the piston at BDC. Look in the plug hole and it'll be pretty straightforward!

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Ditto on last remark, Y-pipe needs come off and small light will tell yah where the burn is. Or, you can watch your spark plg electrodes, if the electrode is dry all the way to the corner, or around, you are definitely in trouble my friend, time to drop the 1371 needles, or better some oil in the gas to keep the motor from seizing.

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I use a small LED bendy light and look down through the spark plug hole, that is the easiest way to check piston wash without the hassel of having to remove the exhaust system, doing it with the bendy light lets you be able to check the piston wash while out riding or testing in the field, also remember when checking plug color if you start with a brand new set of plugs its gonna take at least 20 miles of running the sled before you will acheive color, you just can't throw in a set of plugs make a WOT run and check them for color, if you do it that way the plugs will still look white and scare you into thinking your having a lean condition, and also when doing wash and plug color testing make sure once you get the sled runout to WOT keep the throttle held wide open after shutting down the engine until you come to a complete stop, the following two pictures are of my spare set of pistons that came out of my old motor, these pistons have well over 6000 miles on them and are still in excellent condition, the clean spots on the tops of the domes is the "wash" that you will be looking for, typically if you don't have ANY "wash" marks it is lean, if the tops of the pistons are totally clean then that would indicate a "rich" condition, what you see on these pistons is what I shoot for some may say that this it too lean but I have not smoked a piston in over 6 years jetting and tuning my sleds the way I do, a month or so back I saw a thread over on HCS that was discussing this topic and someone put up a couple of different performance shops opinions of what good piston wash should look like, one of the shops was Bikeman's and I can't remember the other two shops that were compared.

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just an FYI.. discussed it here
http://www.snowmobilefanatics.com/forum/topic/68693/display.aspx

And here recently with the links the guy above is speaking about http://www.snowmobilefanatics.com/forum/topic/84341/display.aspx?post=854579

I think the post he is talking about on HCS came from me actually.

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Good stuff ACM, thats exactly the the topic from over on HCS that I was talking about, and like I said some may say that whats acceptable for me may not be for them, I jet and tune my sleds for all out performance and try to get every bit out of them I can, I have had failures in the past but in recent years nothing but good strong performance and results from my setups.

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